Project Management

Realistic reliability and maintainability objectives need to be set with due regard to the customer’s design and operating requirements and cost constraints. Some discussion and joint study with the customer may be required to establish economic reliability values which sensibly meet his requirements and are achievable within the proposed technology at the costs allowed for. Over-specifying the requirement may delay the project when tests eventually show that objectives cannot be met and it is realised that budgets will be exceeded. When specifying an MTBF it is a common mistake to include a confidence level, in fact the MTBF requirement stands alone. The addition of a confidence level implies a demonstration and supposes that the MTBF would be established by a single demonstration at the stated confidence. On the contrary, a design objective is a target and must be stated without statistical limitations.